Spark ignition internal combustion engine

Abstract

A spark ignition internal combustion engine is equipped with a fuel pressure sensor for detecting a viscosity of fuel supplied to a fuel injector based on a variation in a fuel pressure. In a case of stratified combustion by a spray guided injection, an ECU advances a fuel injection start timing of the fuel injector 4 according to the detected viscosity of the fuel. Thus, even if the viscosity of the fuel is significantly high, the fuel-rich area is well formed at a vicinity of the discharge electrode so that a preferable combustion condition can be maintained.

What is claimed is: 
     
       1. A spark ignition internal combustion engine in which a fuel starts to be combusted by a spark generated by a spark plug, the spark ignition internal combustion engine comprising:
 a fuel viscosity detector which detects a viscosity of the fuel; 
 a fuel injector which injects the fuel into a cylinder of the spark ignition internal combustion engine; and 
 a controller which varies at least one of a fuel injection timing and a fuel injection control pattern of the fuel injector according to the viscosity of the fuel detected by the fuel viscosity detector; wherein 
 the fuel injector directly injects the fuel into the cylinder, and 
 the controller varies at least one of the fuel injection timing and the fuel injection control pattern of the fuel injector according to the viscosity in a case that a stratified combustion is conducted. 
 
     
     
       2. A spark ignition internal combustion engine according to  claim 1 , wherein
 the controller advances the fuel injection timing of the fuel injector according to the detected viscosity of the fuel when it is determined that the detected viscosity of the fuel is higher than a viscosity of gasoline at normal temperature. 
 
     
     
       3. A spark ignition internal combustion engine according to  claim 1 , wherein
 the controller advances the fuel injection timing of the fuel injector and performs a split injection according to the detected viscosity of the fuel when it is determined that the detected viscosity of the fuel is higher than a viscosity of gasoline at normal temperature. 
 
     
     
       4. A spark ignition internal combustion engine in which a fuel starts to be combusted by a spark generated by a spark plug, the spark ignition internal combustion engine comprising:
 a fuel viscosity detector which detects a viscosity of the fuel, 
 a fuel injector which injects the fuel into a cylinder of the spark ignition internal combustion engine; 
 a vortex generating portion which generates a vortex flow in the cylinder; and 
 a controller which controls the vortex generating portion in such a manner that an intensity of the vortex flow is varied according to the viscosity of the fuel detected by the fuel viscosity detector, wherein: 
 the intensity of the vortex flow is varied so as to be increased as the detected viscosity of the fuel becomes higher; 
 the fuel injector directly injects the fuel into the cylinder; and 
 the controller controls the vortex generating portion in a case that a stratified combustion is conducted. 
 
     
     
       5. A spark ignition internal combustion engine according to  claim 4 , wherein
 the controller controls the vortex generating portion so that the intensity of the vortex flow is increased when it is determined that the detected viscosity of the fuel is higher than a viscosity of gasoline at normal temperature. 
 
     
     
       6. A spark ignition internal combustion engine according to  claim 1 , wherein
 the fuel viscosity detector detects the viscosity of the fuel based on a variation in fuel pressure due to an operation of the fuel injector. 
 
     
     
       7. A spark ignition internal combustion engine according to  claim 1 , wherein
 the fuel viscosity detector detects the viscosity of the fuel based on a displacement rate of a needle valve of the fuel injector.